Select an example of the type of design you expect to be involved in during your career

1. Select an example of the type of design you expect to be involved in during your career • Boeing Dreamliner • Wind Energy system • Bionic body parts • High tech R&D • Game software • other

2. Describe the design team • Typical number of people • Areas of responsibility Describe the process from cradle to grave • Societal need • Initial concept

3. A New Design Process Paradigm: Sustainable System Design • Brief Historical Context • Traditional Design Paradigm • Why owners/managers should be flogged! • A Better Paradigm • Additional background Developed by Virginia Tech Professor John C. Duke, Jr. with support of a Faculty Grant of the American Society for Nondestructive Testing, Inc.

4. Why Sustainable System Design? • Numerous major systems are in-service beyond the original design life because replacement of these systems is not a high priority. • Systems operated beyond their service life behave unpredictably and are difficult to manage. • Maintenance of systems in use beyond their service life is costly because it was not anticipated during the planning and design process.

5. Critical Systems Beyond Their Service Life

6. Roman Aqueducts Curator Aquarum was responsible for designing and planning so the aqueducts could be maintained.

7. 2008 Infrastructure Renewal Price Tag • Worldwide estimates $53,000,000,000,000 ($53T) • US estimates within the next 5 years $1,500,000,000,000 ($1.5T)

8. “those who ignore history are doomed to repeat it…” • For the most part traditional engineering design has resulted in systems which perform well during the intended service life. • For the most part these systems are in use beyond the intended service life. • Needless to say these systems were not designed to be maintain in service beyond the intended service life.

9. Traditional Engineering Design • Philosophy general – design, make sure it’s built as designed, operates as designed, do minor maintenance, decommission • Philosophy specific – select materials based on specified performance limits, size the components so that the stress levels avoid overload or failure due to fatigue or environmental effects

10. It is suggested that the instructor show an episode or portion of an episode of the National Geographic World’s Toughest Fixes in order to emphasize the magnitude of the effort required to repair major systems. Encourage the students to look for ways that the design might have been altered to facilitate such repair as well as ways to monitor the system to provide an early warning of the need for repair.

11. Traditional design mindset • Creating a system which will not fail during the established service period. • Avoid issues with difficult to access components. • Details of damage development irrelevant since by design they will not become important until after the service life. • Maintenance is limited to minor issues such as replacing light bulbs or changing lubricants.

12. In the USA most major systems are designed and built for an owner. Designer/builder Owner/operator Airline operator Utility operator Municipality/water authority • Aircraft manufacturer • Power plant construction contractor/system manufacturer • Mechanical contractor for water distribution systems In the USA the owner/operator is responsible for maintenance, which is intended to be minor during the service life.

13. Since we are designing to avoid failure our mechanical testing is conducted to support this approach. • Components are sized to limit the stress below strength limits. (uniaxial tension) • Components are sized to lower the stress so the cycles in service can be accommodated. (S-N curve) 7075-T6 Al

14. Our properties databases offer no insight into when and where degradation occurs even though technology exists to detect and track it. Life: 1.1 million cycles (N=0  failure) 50 μm

15. Traditional Design Process • Define Functional Requirements • Formulate Initial Concept • Assess with respect to Service Requirements • Derive requirements for materials • Determine subcomponents • Revise Initial Concept • Reassess with respect to Service Requirements • Refine materials selection • Real or Virtual Prototype Trials • Refine Concept • Develop Manufacturing Process(es) • Refine Concept & Manufacturing • Begin Production

16. Traditional Scheme Quality Assurance NDI + Commissioning • Requirements • capabilities • service life NDI to support minor maintenance Planning & Design Fabrication Operation/Service • Constraints • cost • environment Condition Design Life

17. Why owners/managers should be flogged! • Traditional design expects that once the system, structure, or component reaches the design life it will be replaced. • Invariably owners/managers observe that many critical, costly systems are still functioning at the design life … so why not continue to use them… LIFE EXTENSION • You don’t extend life you extend USE!!!

18. Quality Assurance NDI + Commissioning • Requirements • capabilities • service life Planning & Design Fabrication Operation/Service • Constraints • cost • environment Condition Design Life Life Extension Traditional Scheme w/Life Extension NDI to support minor maintenance Region not well defined so it was avoided with the original design Note- The “Condition” plot is hypothetical since typically the condition is not being monitored.

19. Overlooked Consequences of Use-Extension • Assessing systems to justify Use-Extension is especially expensive since the design did not anticipate this need. • Some components may be inaccessible so it is not possible to determine their current condition • Assessing components prior to the formation of cracks which can be reliably detected is not currently possible so remaining useful life is difficult to estimate. • Detailed assessment of degradation is needed to determine how it will be affected by the operating environment.

20. A Better Paradigm in Light of Reality • Consider maintenance and associated inspection during the initial planning and design phases--- why and when do materials degrade and components start to fail?

21. Sustainable Design-The details • Define Functional Requirements • Formulate Initial Concept • Assess with respect to Service Requirements • Derive requirements for materials • Identify the chemical, thermal, and mechanical environment • Establish how the materials will degrade • Determine subcomponents • Identify damage modes that should be expected for these materials under these environmental conditions • Provide accommodation, where appropriate, for monitoring technology • Determine that maintenance and associated inspection can be accomplished reliably and cost-effectively

22. The details (continued) • Revise Initial Concept • Reassess with respect to Service Requirements • Refine materials selection • Real or Virtual Prototype Trials • Refine Concept • Develop Manufacturing Process(es) • Refine Concept & Manufacturing • Assure that design changes to facilitate manufacturing do not negatively impact maintenance and associated inspection • Begin Production

23. Sustainable Design • Requirements • capabilities Commissioning Planning & Design Fabrication Operation/Service & Maintenance • Constraints • cost • environment Condition • Health Management Plan • Deterioration Processes • Inspection Requirements • Health Monitoring Requirements • Maintenance • repair • replacement

24. Sensing Energy Elements to support sustainable design education • Material Science • Properties • Modes of degradation • Manufacturing Processes and defects • Mechanical Behavior • Fatigue • Fracture • Creep • NDE capabilities • Method capabilities • Reliability (POD, POI, POF) • Interaction of probing energy with material degradation

25. Modes of Degradation • Instructors may want to consider placing “Materials Degradation and Its Control by Surface Engineering,” by Batchelor et. al. Imperial College Press on reserve for their students. The authors devote the 1st part of the book, written at a very introductory level, to a discussion of the following topics causing materials degradation: • Mechanical • Chemical • Thermal and radiation • Combinations

26. Materials degradation- mechanical • Mechanical causes • Wear • Abrasion • Erosion • Creep • Fatigue • Fracture

27. Materials degradation- chemical • Corrosion of metals • Oxidation reactions with oxygen, sulphur and halogens • Softening/embrittlement of wood and polymers • Corrosion of concrete and ceramics • Dissolution of metals and ceramics in liquid metals and inorganic salts and alkalis • Biochemical and biological modes

28. Materials degradation – Thermal and Radiation • Thermal degradation • Elevated • Cryogenic temperatures • Photochemical • High energy radiation

29. Materials degradation – synergistic effects • Wear in a chemically active environment • Corrosive-abrasive • Corrosive effects on fretting • Abrasive wear in liquid metals • Corrosion fatigue and fracture • Corrosive embrittlement

30. Modes of detecting degradation • Instructors may wish to place on reserve copies of the NASA Special Publication SP-5113, the ASM Materials Handbook volume on Nondestructive Testing, and the American Society for Nondestructive Testing Handbook Series. • The Table-Comparison of Selected NDE Methods (derived from NASA SP-5113) should be distributed to the students as a reference.

31. Modes of detecting degradation – mechanical NDT • Ultrasound • Acoustic Emission • Acousto-ultrasound • Dial gage • Liquid Penetrant • Impact echo • Impulse response • Resonance

32. Modes of detecting degradation- electromagnetic NDT • Magnetic particles • Magnetic flux leakage • Electrical resistance • Eddy current • Infrared thermography • Microwave/radar • Radiography X&N • Optical Fiber gages • Resistance Strain gage • LVDT • Visual

33. Modes of detecting degradation- practical issues Selection of appropriate nondestructive methods depends on: • The nature of the degradation • The process for analyzing the characterization data collected • Constraints associated with the specific application • Access • Environment • Critical imperfection size • Etc.

34. Discipline Experts to support Sustainable design Planning and design teams typically consult discipline experts for in depth input regarding aspects of the design. Examples of discipline experts: • Structural analysis • Loads associated with operation • Materials Since it is unrealistic to expect all design engineers to have strong background knowledge of materials degradation and the associated methods for detecting and tracking it a new discipline expert is needed- NDE Engineer.

35. Case Studies -- It has been reported that Boeing has designed the Dreamliner aircraft so that it can be sustained indefinitely -- Turbine Engine Manufacturers use an approach somewhat similar– see the presentation by Ward Rummel and Carlos Pairazaman “Inspection based Life Management of Fracture Critical Engine Components” -- Examples of problems which might have been avoid by designing for inspectablity are overviewed in the lecture powerpoint with notes “Design for Inspectability”